A charity survey of 2,000 parents revealed that only 25 per cent would know what to do if their baby wasn't breathing.
So St John Ambulance, in partnership with Tesco, has launched a new babygrow designed teach parents how to perform proper infant CPR.
The garment is also designed to reassure the 74 per cent of respondents who said that finding their baby not breathing was the first aid emergency they feared the most.
The CEO of the charity, Sue Killen, said:
We hope the worst will never happen, but the babygrow, and our online video, shows parents what to do in a very clear and simple way.
The instructions are clear and simple:
1. Ring an ambulance immediately
2. Puff over the nose and mouth five times
3. Deliver 30 hard pumps to the centre of the chest, with two fingers only
3. Puff twice
4. Deliver 30 pumps
5. Repeat the last two steps
Picture: St John Ambulance
St John Ambulance has already been noted for its work to inform parents of first aid procedures for babies.
Alex McHugh, of Wigan, told the Huffington Post how she saved her son's life after he stopped breathing at just seven weeks old.
She said she only knew what to do because she had seen a St John Ambulance baby CPR advert just the day before:
It’s every parent’s worst nightmare that their child will stop breathing and this easy-to-understand advice can be the difference between a life lost and a life saved.
From Wednesday, the onesie will be available in Tesco supermarkets from Thursday 13 October - for free, while stocks last - but buyers are encouraged to donate to St John Ambulance.
There will also be a CPR and basic first aid demonstration in some stores.
Michelle McEttrick, group brand director from Tesco, said:
We’re delighted to be supporting St John Ambulance in bringing this lifesaving lesson to parents - a perfect example of Every Little Helps.
More: List of Tesco stores where demonstrations will take place
More: Free 'life-saving' babygrow launched by St John Ambulance and Tesco to teach baby CPR